Camshaft adjusters are technical subassemblies for adjusting the phase angles between a crankshaft and a camshaft in an internal combustion engine.
WO 2011/032805 A1 discloses arranging a volume reservoir in a hydraulically operating camshaft adjuster, in order to avoid a negative pressure in a pressure chamber of the camshaft adjuster.
WO 2011/138136 A1 has disclosed closing a channel between the volume reservoir and the pressure chamber with a non-return valve arranged in the pressure chamber.